Request.RequestContext.RouteData.Values["id"]
, .
ViewDatap >
ViewData["applicationID"] = 1; //or ApplicationModel.Id or whatever
<%: Html.ActionLink("Add New Assistant", "Create", "Assistant", new { applicationID = ViewData["applicationID"] }, null) %>
viewmodel id:
<%: Html.ActionLink("Add New Assistant", "Create", "Assistant", new { applicationID = Model.ApplicationID }, null) %>